diff --git a/cMIPS/tests/mac_uart_rx.c b/cMIPS/tests/mac_uart_rx.c
new file mode 100644
index 0000000000000000000000000000000000000000..bc0e2b55ae031470cdcf29e917f4afceb170aa94
--- /dev/null
+++ b/cMIPS/tests/mac_uart_rx.c
@@ -0,0 +1,122 @@
+//========================================================================
+// UART receive functional test
+// Linux computer must be connected via USB-serial (/dev/ttyUSB0)
+// and must run minicom @ 115.200 bps
+// If all is wall, all typed at minicom's terminal are echoed on the LCD
+//========================================================================
+
+
+#include "cMIPS.h"
+
+typedef struct control { // control register fields (uses only ls byte)
+ int ign : 24, // ignore uppermost bits
+ rts : 1, // Request to Send
+ ign2 : 2, // bits 6,5 ignored
+ intTX : 1, // interrupt on TX buffer empty (bit 4)
+ intRX : 1, // interrupt on RX buffer full (bit 3)
+ speed : 3; // 4,8,16..256 tx-rx clock data rates (bits 0..2)
+} Tcontrol;
+
+typedef struct status { // status register fields (uses only ls byte)
+ int s;
+ // int ign : 24, // ignore uppermost bits
+ // ign7 : 1, // ignored (bit 7)
+ // txEmpty : 1, // TX register is empty (bit 6)
+ // rxFull : 1, // octet available from RX register (bit 5)
+ // int_TX_empt: 1, // interrupt pending on TX empty (bit 4)
+ // int_RX_full: 1, // interrupt pending on RX full (bit 3)
+ // ign2 : 1, // ignored (bit 2)
+ // framing : 1, // framing error (bit 1)
+ // overun : 1; // overun error (bit 0)
+} Tstatus;
+
+#define RXfull 0x00000020
+#define TXempty 0x00000040
+
+
+typedef union ctlStat { // control + status on same address
+ Tcontrol ctl; // write-only
+ Tstatus stat; // read-only
+} TctlStat;
+
+typedef union data { // data registers on same address
+ int tx; // write-only
+ int rx; // read-only
+} Tdata;
+
+typedef struct serial {
+ TctlStat cs;
+ Tdata d;
+} Tserial;
+
+
+#if 0
+char s[32]; // = "the quick brown fox jumps over the lazy dog";
+#else
+// char s[32]; // = " ";
+#endif
+
+int main(void) { // receive a string through the UART serial interface
+ // and write it to the LCD display
+ volatile Tserial *uart; // tell GCC not to optimize away code
+ volatile Tstatus status;
+ Tcontrol ctrl;
+ int i,n;
+ int state;
+ char c, s[32];
+
+ LCDinit();
+
+ LCDtopLine();
+
+ LCDput('c');
+ LCDput('M');
+ LCDput('I');
+ LCDput('P');
+ LCDput('S');
+ LCDput(' ');
+ LCDput('s');
+ LCDput('a');
+ LCDput('y');
+ LCDput('s');
+ LCDput(' ');
+ LCDput('H');
+ LCDput('I');
+ LCDput('!');
+
+ LCDbotLine();
+
+ uart = (void *)IO_UART_ADDR; // bottom of UART address range
+
+ ctrl.ign = 0;
+ ctrl.rts = 0;
+ ctrl.ign2 = 0;
+ ctrl.intTX = 0;
+ ctrl.intRX = 0;
+ ctrl.speed = 3;
+ uart->cs.ctl = ctrl;
+
+ LCDput(':');
+ LCDput(' ');
+
+ n = 0;
+ do {
+
+ while ( ( (state = uart->cs.stat.s) & RXfull ) == 0 )
+ ;
+ c = (char)uart->d.rx;
+ DSP7SEGput( state>>4 , 0, state & 0xf, 0);
+ LCDput(c);
+
+ // cmips_delay(12500000);
+ n = n + 1;
+ if ( n == 16 ){
+ LCDbotLine();
+ n = 0;
+ }
+
+ } while (1 == 1);
+
+ return 0;
+
+}
diff --git a/cMIPS/tests/mac_uart_tx.c b/cMIPS/tests/mac_uart_tx.c
new file mode 100644
index 0000000000000000000000000000000000000000..9e2c6ed065b4bfd20ffce9c47bc536fbbaae9cb0
--- /dev/null
+++ b/cMIPS/tests/mac_uart_tx.c
@@ -0,0 +1,131 @@
+//========================================================================
+// UART transmit functional test
+// Linux computer must be connected via USB-serial (/dev/ttyUSB0)
+// and must run minicom @ 115.200 bps
+// If all is well, minicom's screen shows, forever, '0'..'9''\n'...
+//========================================================================
+
+
+#include "cMIPS.h"
+
+typedef struct control { // control register fields (uses only ls byte)
+ int ign : 24, // ignore uppermost bits
+ rts : 1, // Request to Send
+ ign2 : 2, // bits 6,5 ignored
+ intTX : 1, // interrupt on TX buffer empty (bit 4)
+ intRX : 1, // interrupt on RX buffer full (bit 3)
+ speed : 3; // 4,8,16..256 tx-rx clock data rates (bits 0..2)
+} Tcontrol;
+
+typedef struct status { // status register fields (uses only ls byte)
+ int s;
+ // int ign : 24, // ignore uppermost bits
+ // ign7 : 1, // ignored (bit 7)
+ // txEmpty : 1, // TX register is empty (bit 6)
+ // rxFull : 1, // octet available from RX register (bit 5)
+ // int_TX_empt: 1, // interrupt pending on TX empty (bit 4)
+ // int_RX_full: 1, // interrupt pending on RX full (bit 3)
+ // ign2 : 1, // ignored (bit 2)
+ // framing : 1, // framing error (bit 1)
+ // overun : 1; // overun error (bit 0)
+} Tstatus;
+
+#define RXfull 0x00000020
+#define TXempty 0x00000040
+
+
+typedef union ctlStat { // control + status on same address
+ Tcontrol ctl; // write-only
+ Tstatus stat; // read-only
+} TctlStat;
+
+typedef union data { // data registers on same address
+ int tx; // write-only
+ int rx; // read-only
+} Tdata;
+
+typedef struct serial {
+ TctlStat cs;
+ Tdata d;
+} Tserial;
+
+
+#if 0
+char s[32]; // = "the quick brown fox jumps over the lazy dog";
+#else
+// char s[32]; // = " ";
+#endif
+
+int main(void) { // receive a string through the UART serial interface
+ // and write it to the LCD display
+ volatile Tserial *uart; // tell GCC not to optimize away code
+ volatile Tstatus status;
+ Tcontrol ctrl;
+ int i,n;
+ int state;
+ char c, s[32];
+
+ LCDinit();
+
+ LCDtopLine();
+
+ LCDput('c');
+ LCDput('M');
+ LCDput('I');
+ LCDput('P');
+ LCDput('S');
+ LCDput(' ');
+ LCDput('s');
+ LCDput('a');
+ LCDput('y');
+ LCDput('s');
+ LCDput(' ');
+ LCDput('h');
+ LCDput('i');
+ LCDput('!');
+
+ LCDbotLine();
+
+ uart = (void *)IO_UART_ADDR; // bottom of UART address range
+
+ ctrl.ign = 0;
+ ctrl.rts = 0;
+ ctrl.ign2 = 0;
+ ctrl.intTX = 0;
+ ctrl.intRX = 0;
+ ctrl.speed = 3;
+ uart->cs.ctl = ctrl;
+
+ c = '0';
+ n = 0;
+
+ do {
+
+ while ( ( (state = uart->cs.stat.s) & TXempty ) == 0 )
+ ;
+ uart->d.tx = (int)c;
+ DSP7SEGput( state>>4 , 0, state & 0xf, 0);
+ LCDput(c);
+
+ n += 1;
+ c = (char)((int)c + 1);
+
+ cmips_delay(6125000);
+
+ if ( n == 10 ) {
+ while ( ( (state = uart->cs.stat.s) & TXempty ) == 0 )
+ ;
+ uart->d.tx = (int)(0x0a);
+ while ( ( (state = uart->cs.stat.s) & TXempty ) == 0 )
+ ;
+ uart->d.tx = (int)(0x00);
+ LCDbotLine();
+ c = '0';
+ n = 0;
+ }
+
+ } while (1 == 1);
+
+ return 0;
+
+}